What is H. pylori infection, transmission, symptoms, diagnosis and treatment

What is H. Pylori infection, transmission, symptoms, diagnosis and treatment

What is H. Pylori infection?

The full form of H. pylori is Helicobacter pylori earlier also known as Campylobacter pylori. It is a Gram-Negative bacteria, small in size, comma or curved rod in shape, which colonizes only in the mucus layer of the human stomach.

Its genus name helicobacter is derived from its helical shape. Multiple strains of these bacteria also exist and mostly no strains are identical.

Transmission of bacteria

It is mostly transmitted via the oral-fecal route and oral-oral route including contaminated water, foods, and utensils from the bacteria.

Transmission by endoscopy is also possible and can also be transferred via the gastro-oral route from siblings, older children, and parents.


When you get infected with the bacteria, you may not have any symptoms for years. The most clinical features of the infection are gastritis and among these very few cases develop peptic ulcers.


One of the main causes of gastritis is gastric infection with H pylori. These bacteria invade the mucous membrane of the stomach, remain there for years, and slowly weaken it. The weekend or damaged inner lining of the stomach is further damaged by gastric acid and likewise affected person develops gastritis.

Common symptoms in these cases are burning or dull aching pain at the epigastric region which may worse on an empty stomach, nausea, loss of appetite, frequent eructation, gaseous abdominal discomfort, and unexplained weight loss in some cases.

One who was infected as an infant may develop pangastritis while others who had infection from later childhood have predominantly central gastritis.

Peptic ulcer:

Only a few cases develop peptic ulcers that were infected with it. The infection with more aggressive strains of the bacterium, smokers, hectic and stressful lifestyle are more prone to develop ulcers.

How gastric ulcer develops with H pylori infection?

The mechanism of gastric ulcer development isn’t clear yet but probable mechanism includes…

  • Inflammation of mucus lining of the stomach by bacteria leading to epithelial damage.
  • Lack of synthesis of protective prostaglandins by inhibition of cyclogenesis-1 by NSAIDs.
  • Increase in the bile reflux.
  • Impaired perfusion of importance endarteries in cigarette smokers.

Diagnosis of the H. pylori infection

(A) Non-invasive tests

Serological test:

An infected person develops IgG antibodies in the blood against the bacteria after sometimes which can be detected by ELISA method.

This test can give false-negative results in some cases like intake of NSAIDs and atrophic gastritis in elderly persons with lifelong infection.

Urea breath test:

This test is based on the principle that the solution of urea labeled with ¹³CO2 will be introduced in the patient and it will be rapidly hydrolyzed into Ammonia and isotype carbon dioxide by the urease enzyme of H. pylori. The isotype ¹³CO2 is excreted in the expired breath after its absorption across the gastric mucosa via systemic circulation. Detection of ¹³CO2 in expired breath indicates the person is infected with H pylori.

There are mainly two types of isotype. One is radioactive carbon-14 and the other is non-radioactive carbon-13. In this test, mainly non-radioactive carbon-13 is used.

This test is indicated as a screening test for H. pylori, to confirm eradication, and to detect infection in children.

To perform this test medicines like Proton Pump Inhibitors (PPIs) should be discontinued before 14 days and antibiotics should be stopped before 28 days. Then after the test should be done for better results.

Fecal antigen test:

The ELISA method is used to detect H. pylori antigens discharge in the feces. The test is mostly indicated for epidemiological studies of the acquisition of the infection in children.

(B)Invasive tests

Multiple biopsies are taken from the antrum and corpus and the following tests are done to detect the infection.

Biopsy urease test:

It is based on the principle of release of ammonia by the action of urease enzyme by H. pylori. One or two biopsies are placed on a gel or into a solution containing a pH indicator and urea. There is a change in color if the pH is increased.

Bacterial culture:

This is the most accurate and gold standard test for diagnosis of the H pylori infection and also to determine antibiotic resistance of the bacteria.


This test also gives accurate results and other information on the disease of the mucosa. Histology with stains like hematoxylin or eosin is used to detect the bacteria. Special stains like Giesma, Genta, or Cresyl violet are also needed if there is a low level of infection and to detect the characteristic morphology of the H. pylori.


Treatment is based on to control the symptoms and to eradicate the infection.

(A)Control of the symptoms:

Gastritis can be controlled with Proton Pump inhibitors like Omeprazole, Rabeprazole, Lansoprazole, Esomeprazole, H2 blockers like cimetidine, ranitidine, famotidine, and Antacids.

(B)Eradication of infection:

Different triple-drug combinations can be used for one week to eliminate the H. pylori infection like…

OAC or LAC combination:

It contains omeprazole 20 milligram or lansoprazole 30 milligram, amoxicillin 1000 milligram, and clarithromycin 500 milligram. All medicines are given twice a day.

OMC or LMC combinations:

It contains omeprazole 20 milligram or lansoprazole 30 milligram, metronidazole 400 milligram, and clarithromycin 250 or 500 milligram. All medicines are given twice a day.

Quadruple-drug therapy:

In this four medicine combinations are used like Omeprazole 20 mg, Bismuth subcitrate 120 mg, tetracycline 500 mg, and metronidazole 400 mg. It is used when triple-drug combinations failed to eradicate the infection.

Side effects:

The most common side effects of the antibiotics used in this combination are disturbed abdomen mostly diarrhea and metallic taste in the mouth.

Many times there is also a chance to develop resistance to these antibiotics. In such cases, it is difficult to eliminate the infection.

This is for educational purposes only. Please consult your doctor before taking any action.

How to prevent H. pylori infection?

“Prevention is better than Cure” this gold standard rule is also applied in this case. The primary source of transmitting the infection is fecal-oral and oral route but it can also be transmitted by unhygienic drinking water, food, and other environmental sources also. Children are more vulnerable to get infection. So following preventive measures should be carried.

Educating the parents is most important as getting an infection to a child from mother and sibling is most common. Educating them about sanitization prevents the risk of getting infection.

Washing hands thoroughly especially before breast-feeding the child, arranging drinking water from safe and clean sources, eating food that is properly prepared and cooked. All these measures reduce the chances of infection.

H Pylori infection FAQs

What is H pylori ICD 10?

Different diseases are classified in the different codes in ICD which means International Classification of Diseases and ICD 10 is its 10th version.
In ICD 10 certain infectious and parasitic diseases are coded from A00-B99 and Bacterial and viral infectious agents from B95 – B97. B96.81 is the code for Helicobacter pylori as the cause of diseases classified elsewhere in the ICD 10 classification.

What is H pylori antigen test?

A person who is infected with Helicobacter pylori bacteria sheds the antigen in their feces. So antigen test is the Elisa method for detecting antigen of the bacteria in the stool of a patient. Mostly this test is conducted for epidemiological studies when many children are affected by the infection.

Can H pylori cause cancer?

Yes. It may cause gastric cancer. It is one of the strongest risk factors for developing gastric cancer including duodenal and gastric ulcers. But most of people with this infection have no symptoms and if diagnosed earlier and treated well we can prevent the chances of cancer development. You can read a detailed study here.

Is H pylori Contagious?

Yes. Children are more prone to get infections from parents, siblings, and the persons taking care of them. It can be transmitted by the fecal-oral and oral-oral routes and also by taking infected water and food with the bacteria. So maximum care should be taken to prevent the infection via this mode.

What is the blood test to diagnose H pylori infection?

Performing a blood test to detect H. pylori infection is a non-invasive method of diagnosis. Blood of the affected person is taken and an ELISA test is done to detect antibodies produced by our body against the bacteria. Likewise, an antigen test is done to detect the antigen of the bacteria in our body. But for antigen detection, mostly stool of an infected person is used.

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